Gluconic acid as a fresh beef decontaminant

Effectiveness of 0, 1.5 and 3.0% gluconic acid (G) and/or 0 and 1.5% lactic acid (L) solutions in reducing aerobic psychrotrophic bacteria plate counts (PPCs) and lactic acid bacteria counts (LACs) on vacuum-packaged beef was investigated at 0, 14, 28 and 56 days of storage. Instrumental and visual color changes were evaluated up to 28 days. Steaks treated with 1.5% L, plus 1.5% G or 3.0% G, solutions showed 2.0 and 2.5 log reductions (P0.05) in PPCs compared to nontreated samples, respectively, at days 28 and 56. At 1.5%, G or L intervention for 0 and 14 days PPCs did not differ (P0.05). However. PPCs were lower (P0.05) for samples treated with 1.5% L than with 1.5% G at 28 and 56 days of storage. The effect of G plus L in reducing (P0.05) LACs was evident at all storage periods. Inoculation with Lactobacillus fermentum (10(4) colony forming units [CFU]/ml) resulted in higher (P0.05) PPCs and LACs at 28 and 56 days compared to noninoculated counterparts. Increasing G from 1.5 to 3.0% decreased (P0.05) redness and increased (P0.05) yellowness at day 0. Samples treated with 1.5% L solution had numerically the lowest a* values at days 0 and 14. This detrimental effect was reduced (P0.05) when 1.5% G was added in combination with L, because redness increased (P0.05) at day 14. At 0 day, 1.5% L steaks showed the fastest (P0.05) rate of color deterioration. At 14 days, the presence of L alone or in combination with 1.5 or 3% G resulted in steaks with slightly faster (P0.05) color deterioration compared to steaks treated with G or not treated. At day 28, 3.0% G samples revealed the fastest (P0.05) color deterioration. This detrimental effect on color was reduced (P0.05) when G plus L was applied at 1.5%